1. Field of the Invention
The present invention relates to a trouble diagnosis apparatus for an internal combustion engine which judges troubles such as a combustion trouble, an ignition trouble or the like in the internal combustion engine.
2. Discussion of Background
Heretofore, a voltage at the primary winding of the boosting coil is detected to monitor the ignition state of the engine. When there is found that the coil produces a voltage at the primary winding side, it is judged that the engine normally performs igniting operations.
However, since the conventional technique relys on estimation, it can not judge that the engine certainly performs combustion and igniting operations.